Variables  are distinguished by an initial capital letter or by the initial
character "_", eg.

                          X Value A   A1  _3   _RESULT

If  a  variable  is only referred to once, it does not need to be named and
may  be  written as an "anonymous" variable indicated by a single underline
character:-
                                       _

A  variable  should  be  thought  of  as  standing  for  some  definite but
unidentified  object.  This is analogous to the use of a pronoun in natural
language.   Note that a variable is not simply a writeable storage location
as  in  most programming languages; rather it is a local name for some data
object.
